Variable frequency radio frequency identification (RFID) tags
First Claim
1. A radio-frequency identification (RFID) tag comprising:
- a main antenna tuned to a first resonant frequency;
switching circuitry that dynamically changes the resonant frequency of the main antenna; and
a sensing circuit to sense electromagnetic coupling with a neighboring RFID tag and activate the switching circuit in response to the sensed eletromagnetic coupling.
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Accused Products
Abstract
Various radio frequency identification (RFID) tags are described that dynamically vary their resonant frequency to reduce or eliminate the potential effects of electromagnetic “tag-to-tag” coupling. An RFID tag, for example, includes a main antenna tuned to a first resonant frequency, and switching circuitry that dynamically changes the resonant frequency of the main antenna. The switching circuitry may selectively couple electrical elements, such as capacitive elements, inductive elements, or combinations thereof, to vary the resonant frequency of the RFID tag. The RFID tag may include a sensing circuit that determines when to selectively couple the electrical element to the main antenna to adjust the resonant frequency of the main antenna.
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Citations
38 Claims
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1. A radio-frequency identification (RFID) tag comprising:
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a main antenna tuned to a first resonant frequency; switching circuitry that dynamically changes the resonant frequency of the main antenna; and a sensing circuit to sense electromagnetic coupling with a neighboring RFID tag and activate the switching circuit in response to the sensed eletromagnetic coupling. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method comprising:
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operating a main antenna of a radio frequency identification (RFID) tag at an associated resonate frequency; sensing an amount of electromagnetic coupling between the RFID tag and a neighboring RFID tag; and dynamically changing the resonant frequency of the main antenna based on the sensed amount of electromagnetic coupling. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24)
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25. A radio frequency identification (RFID) system comprising:
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an RFID interrogation device; an RFID tag associated with an article, wherein the interrogation device interrogates the RFID tag to obtain information regarding the article; and a computing device to process the information retrieved from the RFID interrogation device, wherein the RFID tag includes a main antenna tuned to a first resonant frequency, an integrated circuit electrically coupled to the main antenna that stores information of the associated article, switching circuitry that selectively couples one or more elements to the main antenna to adjust the resonant frequency of the main antenna, and a sensing circuit to sense electromagnetic coupling with a neighboring tag and activate the switching circuit in response to the sensed electromagnetic coupling. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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Specification